Internal combustion engine



June 23, 1942. E ETAL I 2,287,399

INTERNAL COMBUSTION ENGINE Filed Dec. 23, 1959 2 Sheets-Sheet l INVENTORS Marsqien Ware BY Mar'vm J. Steele June 23, 1942- M. WARE ETAL,287,399-

INTERNAL COMBUSTION ENGINE Filed Dec. 23, 1939 -2 Sheets-Sheet 2'INVENTORS Marsden Ware, BY Marvin J. Steele ATTORNEYS Patented June 23,1942 INTERNAL COMBUSTION ENGINE Marsden Ware, Huntington Woods, andMarvin J.

Steele, Detroit, Mich., assignors to Packard Motor Car Company, Detroit,Mich., a corporation of Michigan Application December 23, 1939, SerialNo. 310,676

4 Claims.

This invention relates to internal combustion engines and moreparticularly to engine crankcases having angularly disposed cylindersassociated therewith.

Crankcases of this type, especially those with which the cylinders arein V-relation, usually support the crankshaft in bearings arranged alongone terminal of transversely extending Webs or walls and a sheet metalclosure member for the crankshaft is applied to such wall. This closuremember'is not designed to absorb load and consequently the crankshaftsupporting half of the case structure must absorb substantially allloads resulting from explosions. The stresses are rapidly reversed athigh engine speeds and the casing wall structure must be strong enoughto Withstand all operating stresses.

In the interest of reducing the crankcase weight and increasing itsstress resistance, it isthe practice to secure the crankshaft bearing.20

caps by tension bolts that extend through the bearings and thesupporting webs to the exterior of the crankcase in parallel relationwith the axes of the cylinders. Such bolts are placed in tension so thatexplosion loads on the crankshaft bearings and the associated webscaused by explosions in the engine cylinders will be well distributed.

While this bearing cap securing arrangement allows reduction incrankcase wall thickness due.

to the compression of the crankcase webs in directions parallel with theaxes of the cylinders, the crankcase webs extending outside of the tiebolts are not materially compressed and unless made relatively thickthey become fractured under the explosion loads.

One of the objects of the present invention is to provide an engine ofthe character designated in which the crankcase is placed undercompression in directions of the axes of the cylinill ders and alsotransversely of the crankshaft bearings.

Another object of the invention is to provide an engine of the characterdesignated in which loads on the crankcase and its transverselyextending webs, caused by explosions in the engine cylinders, are'takendirectly by members in tens1on,

Another object of the invention is to provide a light-weight enginecrankcase in which the walls and webs can be made thin through theemployment of a plurality of tension members ing for crankshaft 2|.

(01 121-194) I are flanged to assist in directions of themajor'stresses.

Other objects of the invention will appear from the followingdescription taken in connection with the drawings, which form a part ofthis specification, and in which:

Fig. 1 is a. transverse vertical section through a portion of a V-typeinternal combustion engine with parts broken away;

Fig. 2 is a sectional view of the engine taken on line 22 of Fig. 1;

Fig. 3 is a sectional view of the engine taken on line 3-3 of Fig. 1;

Fig. 4 i a perspective view of bearing cap;

Fig. 5 is a sectional view of a crankcase similar to Fig. 1, showing amodified form of web;

Fig. 6 is a sectional view taken on line 8-6 of Fig. 5.

Referring to the drawings, Ill indicates generally the crankcase or aninternal combustion engine on the angular. top wall ll of which an-.gularly disposed pairs of cylinders l2 and I3 are secured by bolts H.The crankcase is in the form of a shell having lugs l5 extending fromthe side walls It thereof by means of which the engine may be mountedand secured upon a suitable base, The lugs are preferably cast integralwith the crankcase and extend horizontally.

The crankcase is'provided with transversely extending internal Webs l1preferably cast integral therewith and arranged one between each pair.of cylinders. The webs are provided-with a crankshaft suitable openingsH to lessen their weight and 'theaxis of theadjacent cylinder. .Thecentral bottom wall portion 19 of the webs lying between the angularfaces is formed as a semi-circular bearing to receive the upper section20 of a bush- The bottom wall faces22 of the webs adjacent the sides ofthe crankcase extend horizontally and are joined with the angular facesill by vertically extending faces 22'.

disposed in at least three angular relationships.

A further object of the invention is to provide a crankcase structure inwhich the interior webs The bottom wall of the crankcase is 'covered by'a removable sheet metal pan 23 forming a sump for the engine lubricatingsystem.

Beneath each of the webs I1 is arranged a bearing cap 24 which maybeformed of suitable material. Such caps each have faces 25 and 26respectively complementaryto the web faces I8 and 22', and anintermediate semi-circular face 21 adapted to receive the lowercrankshaft bushing section 28.

Each crankcase web l1 and its associated cap through the side walls ofthe crankcase.

24 is provided with a pair of aligned holes 29 in which tension members30 are disposed. These members 30, preferably in the form of tie bolts,extend through the holes in the caps and the webs and through the uppercrankcase wall H where they are secured'by nuts 3|. By turning the nutsdown on the bolts, after engaging the crankcase, the bolts will beplaced in tension so that the crankcase will be held in compression inthe direction of the axis of the bolts. Obviously the bolts will alsoserve to secure the bearing caps in assembled position. The nuts 3| maybe provided with any suitable locking means such as the lock nuts 32.These tension bolts add strength to the crankcase so that it canwithstand greater stresses in the axial zone of the cylinders.

The portions of the webs extending outside of the bolts 30 are subjectedto deflection and fracture induced by bending movements resulting fromperiodic forces existing in the crankshaft as the cylinders are firedalternately in the respective cylinder banks. In order to permit the useof a thin web and still overcome this condition without materiallyincreasing weight, it is proposed to provide reinforcing ribs and alsotension means for placing the webs in compression horizontally.

The sides of the caps. are provided with vertically extending undercutgrooves 33 for anchoring the heads of tension bolts 34 that extendhorizontally through openings 35 in the webs and Nuts 35 are screwed onthe threaded outer ends of the bolts against the casing side wallssufli'ciently to compress the web portions through which the boltsextend. The grooves 33 are coextensive with the side portions of thecaps so that the bolts 34 can be positioned in the webs prior toassembly of the caps. These tensioned bolts 34 serve to secure thebearing caps in assembled position with the'webs as well as placing thecrankcase under compression in a horizontal direction.

As a further means of strengthening the thin webs in the crankcase,integral flanges or ribs are provided. One such rib 40 follows theoutline of the bottom face of each web and projects beyond both verticalfaces thereof in a direction axially of the crankshaft; Each web isfurther reinforced by flanges or ribs 4| extending at an angle to thehorizontal and joining ribs 40 with the side walls of the crankcasepreferably about midway between the adjacent bolts 30 and 34. As shownin Fig. 1, these reinforcing flanges 4| extend upwardly from thehorizontal in a direction away from the adjacent crankcase side wallwhile'in Fig. such flanges 4| extend downwardly from the horizontal in adirection away from the adjacent side wall of the crankcase. Such ribswill reinforce the webs to resist fracture under load resulting fromapplied crankshaft forces.

With the tension means herein described the crankcase is placed incompression in a plurality of directions radially of the crankshaft.Because of such tension means and reinforcing ribs, the walls of thecrankcase can be made relatively thin without danger of fracture fromexplosion-induced forces.

Although the invention has been described in connection with a specificembodiment, the principles involved are susceptible of numerous otherapplications which will readily occur to persons skilled in the art. Theinvention is therefore to be limited only as indicated; by the scope ofthe appended claims.

What is claimed is:

1. An internal combustion engine casing comprising a crankcase shellhaving angularly disposed pairs of cylinders fixed on the top wallthereof, relatively thin webs formed integral with the shell andextending transversely thereof in planes between the adjacent pairs ofcylinders, said webs having a bottom face with a central crankshaftbearing portion and portions adjacent the bearing portion extendingoutwardly and downwardly, bearing cap structures having facescomplementary to and bearing against the outwardly and downwardlyextending portions of the bottom faces of the webs, angularly disposedbolts of relatively large diameter extending through the shell, the websand the cap structures in a relation parallel to the axes of the pairsof adjacent cylinders and outside of the crankshaft bearing portionsthereof, means securing the bolts in tension to compress the caps, websand crankcase adjacent thereto, bolts anchored to the bearing capsoutside of the angularly disposed tension bolts and'extendinghorizontally through the webs and the shell, and securing means appliedto the ends of the horizontally extending bolts exteriorly of the shellin a relation to place the bolts in-tension and holding the portions ofthe webs and crankcase adjacent-the horizontal bolts under compression.

2. In an internal combustion engine, a crankcase having two rows ofcylinders in angular relation thereon, webs integral with and extendingacross the interior of the crankcase between the pairs of cylinders inthe two rows, the base walls of the webs each having a crankshaftbearing portion above the bottom of the crankcase and extendingdownwardly at an angle normal to the cylinder axes at each side of thebearing and then vertically to form angular seat portions, a bearing caphaving angular and vertical wall portions complementary to and bearingagainst portions of each web, the vertically extending wall portions ofthe caps having undercut grooves therein, a pair of angularly disposedbolts extending through each associated web and cap and the crankcase inparallel relation to the respective cylinder rows, said bolts passingthrough the downwardly extending base portions of the webs and capsoutside of the bearing portions thereof, said bolts compressing portionsof the crankcase, webs and caps adjacent thereto, a second pair of boltsextending through the portions of each web lying outside of the verticalseats and to the exterior of the crankcase, the

heads of the second pair of bolts lying in the undercut grooves in thecaps, and means acting on said latter bolts to place the portions of theweb and crankcase adjacent such bolts in compression.

3. In an internal combustion engine, a crankcase having angularlydisposed cylinders mounted thereon and having transverse integral websfor supporting the crankshaft bearings, said web having a bearingreceiving recess and formed with angular faces extending from saidrecess and with separated parallel faces extending vertically from theouter ends of said angular faces, a bearing cap for each web formed witha bearing recess and having angular and separated parallel'facescomplementary to the angular and parallel faces of said web, said capfilling the space between the parallel faces of said web, bolts parallelwith the cylinder axes extending through said cap and web securing thecap in place around the crankshaft bearing, and separated substantiallyaligned bolts connected to the cap therein, a cap having a.complementary bearing recess and having portions extending laterallythereof, said portions each having vertical undercut grooves thereln,bolts mounted horizontally in the webs laterally of the bearing recessesand having their heads separated substantially the distance betweentheundercut grooves of the cap so that thebolt heads will enter thegrooves as the bearing cap is m'oved upwardly into place.

' means arranged between the bearing recess and said grooves forsecuring the bearing cap in position, and means operating with saidbolts to 10 clamp the bearing cap to the web.

MARSDEN WARE. MARVIN J. STEELE

